DE102004063088A1 - Organic electroluminescent device and manufacturing method for such - Google Patents

Abstract

To fabricate an organic electroluminescent device, the following steps are performed: fabricating a thin film transistor (T¶D¶) on a substrate (500); Forming a passivation layer (560) and a first electrode (570) on the substrate (500) with the thin film transistor (T¶D¶); Forming a contact hole (572) exposing the top of a drain electrode (550) of the thin film transistor (T¶D¶) in a predetermined portion of the first electrode (570) and the passivation layer (560); Forming a buffer layer (580) and a barrier rib (582) on a predetermined part of the top of the first electrode (570); Forming an organic emission layer (590) within a region formed by the buffer layer (580) and forming a second electrode (600) on the organic emission layer (590) such that the second electrode (600) passes through the contact hole (572) electrically is connected to the drain electrode (500).

Description

Priority: March 2004, Rep. Korea (KR), 10-2004-0019937

The Invention relates to an organic electroluminescent device, and more particularly it relates to an organic electroluminescent device, in the case of a thin-film transistor of amorphous silicon is used as the driving element, and a manufacturing method for one such.

liquid crystal displays (LCDs) with the advantage of low weight, a slim profile and low energy consumption were the highlights of public Attention to attracting flat panel displays.

There however, an LCD is a passive device, not a light-emitting device (i.e., active component), it has technical limitations in terms of brightness, contrast, viewing angle, of the big one Umbrella and the like. Therefore, an energetic research was done for new flat panel displays that overcome the disadvantages of LCDs can.

Under Such flat panel displays is an organic electroluminescent device (ELD) a self-emitting display with high contrast and greater viewing angle. An organic ELD can be lightweight compared to other displays and be designed with slim profile, as they have no backlight needed. Also, energy consumption can be compared to other displays be lowered.

Further can an organic ELD with a low DC voltage and high response rate can be controlled. As all components of a organic ELDs are made of solid materials, they are resistant to external shocks. she can also be in a big one Temperature range used and manufactured cheaply.

Especially are, as an organic ELD by just one deposition process and an enclosure process the manufacturing process and the plant are very simple, what about the method of manufacturing an LCD or plasma display panel (PDP) deviates.

Also when driving an ELD in an active matrix way, that every pixel is over one as a switching element functioning computer peripheral device has, even achieved with a low current supply a uniform luminosity become. As a result, an organic ELD shows benefits low Energy consumption, high resolution and a big one Screen.

A Such organic active matrix electroluminescent device (hereinafter referred to as "AMOLED") described below with reference to the accompanying drawings.

The 1 shows a circuit diagram illustrating a basic pixel structure of a relevant AMOLED.

As shown in the drawing, gate lines are GL 2 formed in a first direction and data lines DL 3 as well as voltage lines VDD 4 are formed in a second direction intersecting the first direction to form a unit pixel area.

At each intersection between the gate and data lines 2 and 3 is a switching TFT 5 designed as addressing. With the switching TFT 5 and the voltage line 4 is a storage capacitor C _S 6 connected. A driver TFT 7 which forms a power source element is connected to the storage capacitor C _s 6 and the voltage line 4 connected. With the driver TFT 7 is also an organic electroluminescent diode 8th connected.

When current is supplied to the organic light emitting material in a forward direction, electrons and holes that move through a pn junction between an anode electrode as a hole donor and a cathode electrode as an electron donor recombine. Therefore, the energy of the organic electroluminescent diode 8th lower than how it is generated when the electrons are separated from the holes. In this case, an energy difference is generated, whereby light is emitted.

In other words, a unit pixel of an AMOLED basically has the switching TFT 5 for addressing a pixel voltage forming a gate drive voltage, a driver TFT 7 for controlling a driver current for the AMOLED and a storage capacitor 6 for stably maintaining a pixel voltage.

organic Electroluminescent devices can be found in those from the top emitting and down-emitting type, what is dependent from the propagation direction of that emitted by the organic electroluminescent diode Light takes place.

TFTs used in an AMOLED may change into amorphous ones depending on conditions of a thin-film semiconductor film acting as an active channel silicon (a-Si) and polycrystalline silicon (p-Si).

In younger Time has been devoted to vigorous research on the use of a p-Si TFT with high field-effect mobility in an AMOLED, however It is more typical to use an a-Si TFT in an AMOLED.

The 1 illustrates an AMOLED using a-Si TFTs. The a-Si TFTs are of the n-type. Accordingly, as it is in the 1 is shown, the AMOLED with the source electrode (S) of the driver TFTs 7 connected, and the voltage line 4 is connected to the drain electrode D thereof.

The 2 FIG. 12 is a schematic sectional view illustrating a down-emitting type AMOLED according to a related art. FIG.

As shown in the drawing, the AMOLED of the down-emitting type has a first transparent substrate 12 , an array part made on this 14 as well as an anode 16 , an organic emission layer 18 and a cathode arranged sequentially on the array part 14 are formed and form an organic electroluminescent diode.

At this point, the organic emission layer represents 18 For example, organic materials that emit colors R, G, and B are patterned at each pixel P. Alternatively, the organic emission layer 18 be made with a multilayer structure of organic material.

In other words, the organic electroluminescent layer 18 between the anode and the cathode are formed by sequentially depositing a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), and an electron transport layer (ETL).

The first substrate 12 is on a second substrate 28 on which an absorbent 22 is formed by a sealant 26 to thereby finish the organic electroluminescent device included.

The absorbent 22 serves to remove moisture and oxygen that can penetrate the sealed organic electroluminescent device. Part of the substrate 28 is etched, and the absorbent 22 is filled in the etched part and fixed by a tape.

The 3 FIG. 10 is a sectional view partially illustrating a TFT array part of FIG 1 and 2 illustrated electroluminescent device according to a relevant art. More precisely, it illustrates 3 a cross section of a region with a driver TFT of the TFT array part.

in the Generally, in an AMOLED, each of the pixels is on the substrate formed TFT arrays with a switching element, a driver element and a storage capacitor provided. Depending on the operating characteristics For example, the switching element or the driver element may be a combination consist of more than one TFT.

Both the switching TFT T or 5 as well as the driver TFT T _D or 7 has a gate electrode, an active layer, a source electrode and a drain electrode. Incidentally, the TFTs used in an AMOLED may be classified into a-Si TFTs and p-type Si TFTs depending on states of a thin-film semiconductor thin film.

The 3 illustrates an AMOLED using a-Si TFTs. Here, as stated above, the a-Si TFTs are of the n-type. Accordingly, the anode of the AMOLED is connected to the source electrode (S) of the driver TFT.

According to the 3 the driver TFT T _D has a gate electrode 30 a gate insulating layer 31 , a source electrode 33 and a drain electrode 34 , Between the source electrode 33 and the drain electrode 34 is an active layer 32 arranged.

Also, a pixel area is configured to have one with the source electrode 33 connected anode 36 , an organic emission layer 38 designed as a single layer structure or multi-layered structure on the anode 36 is formed, and one on the organic emission layer 38 Cathode formed to inject electrons 39 features. The anode 36 injects holes into the organic emission layer 38 ,

The organic emission layer 38 with multilayer structure, as stated above, may be configured to have the HIL, the HTL, the EML and the ETL.

The pixel areas are arranged in a matrix configuration and they are through a buffer 37 separated from each other.

In other words, according to the related art, the AMOLED is configured to pass over the pixel T-shaped driver TFT T _D that is connected to the source electrode 33 connected and anode functioning as a pixel electrode 36 on the anode 36 for dividing the pixel areas from each other formed buffers 37 , the organic emission layer from the HIL, the HTL, the EML and the ETL within the buffer 37 as well as those on the organic emission layer 38 formed cathode 39 features.

From the drawings of 1 to 3 For example, it is well understood that the AMOLED is configured in accordance with the relevant technique using an a-Si TFT as the driver TFT to be over the one with the source electrode 33 of the driver TFT T _D connected anode 36 and the organic emission layer 38 as well as the cathode 39 has that on the anode 36 are arranged.

In other words, according to the construction of the AMOLED according to the related art, it works with the source electrode 33 of the driver TFT T _D connected anode 36 as a pixel electrode, and the cathode 39 acts as a counter electrode, ie, as a common electrode, which is opposite to the conventional structure in which the cathode acts as a pixel electrode and the anode acts as a common electrode.

Accordingly, if the pixels of an AMOLED are configured with the above construction, the circuit is not stable, making it a driving error can come.

Accordingly, it is An object of the invention is an organic electroluminescent device and a manufacturing method for to create one that is due to one or more of problems of restrictions and disadvantages in the relevant Essentially avoid technology.

One Advantage of the invention is an organic electroluminescent device and a manufacturing method for to create such, where a driver TFT of each pixel is made of a-Si, a second electrode (i.e., the cathode) of a organic electroluminescent diode having a drain electrode of Driver TFT is connected, and the organic electroluminescent diode over a layer structure that has the same as the conventional one EL, whereby the organic electroluminescent device stable and easy way is controllable.

Around to achieve these and other advantages, and in accordance with the purpose of the invention, how it was realized and comprehensively described here is one Organic electroluminescent device provided with: a plurality of TFTs on a substrate; a passivation layer and a first electrode on the substrate with the TFTs; one Contact hole through a predetermined part of the first electrode and the passivation layer around the top of a drain electrode of the thin film transistor expose; a buffer layer on a predetermined part of Top and one edge of the first electrode; an organic one Emission layer within a formed by the buffer layer range; and a second electrode on the organic emission layer, and electrically through the contact hole with the drain electrode connected is.

According to one Another aspect of the invention is a method for manufacturing an organic electroluminescent device is provided, the Comprising: fabricating a thin film transistor on one substrate; Producing a passivation layer on the substrate with the thin film transistor; Forming a first electrode layer on the passivation layer; Producing a contact hole through the passivation layer and the first electrode layer; Exposing a surface of a Drain electrode of the thin film transistor in a predetermined part of the first electrode and the drain electrode; Forming a buffer layer on a predetermined part of the top the first electrode; Producing an organic emission layer within a region formed by the buffer layer; and Producing a second electrode in such a way on the organic Emission layer that this second electrode through the contact hole through is connected to the drain electrode.

According to one Another aspect of the invention is a method for manufacturing an organic electroluminescent device is provided, the Comprising: fabricating a thin film transistor on one substrate; Producing a passivation layer on the substrate with the thin film transistor; Patterning the passivation layer to form a contact hole; Produce a first electrode layer on the passivation layer; Structure the first electrode layer for making a contact hole, the corresponding to the contact hole through the passivation layer, and exposing the top of a drain electrode of the thin film transistor in one predetermined part of the first electrode and the passivation layer; Producing a buffer layer on a predetermined part of Top of the first electrode; Producing an organic emission layer within a region formed by the buffer layer; and Producing a second electrode on the organic emission layer in such a way that this second electrode through the contact hole through is connected to the drain electrode.

According to one Another aspect of the invention is a method for manufacturing an organic electroluminescent device is provided, the Comprising: fabricating a thin film transistor on one substrate; Producing a passivation layer on the substrate with the thin film transistor; Forming a first electrode layer on the passivation layer; Patterning the first electrode layer to form a contact hole; Patterning the passivation layer to form a contact hole, that corresponds to the contact hole through the first electrode layer, and exposing the top of a drain electrode of the thin film transistor in a predetermined part of the first electrode and the passivation layer; Producing a buffer layer on a predetermined part of Top of the first electrode; Producing an organic emission layer within a region formed by the buffer layer; and Producing a second electrode in such a way on the organic Emission layer that this second electrode through the contact hole through is connected to the drain electrode.

It Please note that both the above general description as well as the following detailed description of the invention by way of example and explanatory are and are intended for another explanation of the claimed invention.

The attached Drawings that are included for further understanding of the Invention, and which are included in this application and forming a part thereof, illustrate an embodiment (Embodiments) of the invention, and together with the description serve to to explain the principle of the invention.

In The drawings show the following.

1 Fig. 12 is a circuit diagram of a basic pixel structure of an AMOLED according to a related art;

2 Fig. 12 is a schematic sectional view of a down-emitting AMOLED according to a related art;

3 is a sectional view of a part with a TFT array part of the in the 1 and 2 presented AMOLED;

4 is a circuit diagram of a basic pixel structure of an AMOLED according to the invention;

5 is a sectional view of a part with a TFT array part of an AMOLED according to the invention;

6A to 6F Fig. 3 are sectional views illustrating a method of manufacturing an AMOLED according to the invention;

7A to 7F Figure 11 are sectional views illustrating another method of making an AMOLED according to the invention; and

8A to 8F FIG. 11 are sectional views illustrating another method of manufacturing an AMOLED according to the invention. FIG.

Now is detailed on embodiments of In the accompanying drawings, examples are given by way of example are shown.

The 4 is a circuit diagram illustrating a basic pixel structure of an AMOLED according to the invention.

According to the 4 are gate lines (GL) 42 formed in a first direction, and data lines (DL) 43 as well as voltage lines (VDD) 44 are spaced a predetermined distance apart in a second direction intersecting the first direction. Through the gate lines 42 , the data lines 43 and the voltage lines 44 Pixel areas are formed.

At every intersection between the gate and data lines 42 and 43 is an acting as an addressing element switching TFT 45 educated. With the switching TFT 45 and ground is a storage capacitor C _s 46 connected.

A driver TFT acting as a current source element 47 is with the storage capacitor C _S 46 and the voltage line 44 connected. With the driver TFT 47 is an organic electroluminescent diode 48 connected.

When current is supplied in a forward direction to the organic light emitting material, electrons and holes recombine, moving through a pn junction between an anode electrode as a hole donor and a cathode electrode as an electron donor. Therefore, the energy of the organic electroluminescent diode 48 lower than that produced when the electrons are separated from holes. At this point, an energy difference is generated, whereby light is emitted.

That is, the basic pixel structure of the AMOLED via the switching TFT 45 to the address a gate drive voltage (ie, a pixel voltage), the driver TFT 47 for controlling a drive current of the AMOLED and the storage capacitor 46 to stably maintain the pixel voltage.

Deviating from the structure of the AMOLED according to the pertinent art is a drain electrode D of the driver TFT 47 with a second electrode (ie, a cathode) of the organic electroluminescent diode 48 connected, and a source electrode S of the driver TFT 47 is connected to ground.

there is the TFT for driving each pixel as an n-type a-Si TFT formed of an amorphous silicon active layer.

The organic electroluminescent device can be stably driven by configuring the driver TFT as an amorphous TFT and the drain electrode D of this driver TFT 47 with the second electrode (cathode) of the organic electroluminescent diode 48 is connected.

That is, the second electrode (cathode) of the organic electroluminescent diode 48 with the drain electrode D of the driver TFT 47 is connected and configured to act as a pixel electrode, while the first electrode (anode) of the organic electroluminescent diode 48 is configured to act as a common electrode. This configuration allows stable control of the AMOLED.

When the TFTs for driving each pixel are configured by amorphous TFTs, the width-to-length ratio (W / L ratio) of the driver TFT must be large to drive the organic light emission layer, since the mobility in amorphous silicon is about 0.5-1 cm ² / Vs lower than that in crystalline silicon.

The Size of the driver TFT must because of the big one W / L ratio same be great. If however, the size of the driver TFT gets too big, there is a problem that the aperture ratio of an organic electroluminescent device is downsized from the down-emitting type.

Therefore For example, it may be preferred that an organic electroluminescent device using amorphous TFTs instead of an up-emitting one works in down-emitting mode.

The 5 is a sectional view of a part with a TFT array part of the invention AMOLED. In the 5 a part is shown with the driver TFT of the TFT array part.

The 5 corresponds to the sectional view in the 3 represented AMOLED according to the relevant art. The positions of the source and drain electrodes of the driver TFT are reversed, and the drain electrode of the driver TFT is not connected to the first electrode (anode) but to the second electrode (cathode) of the organic electroluminescent diode.

According to the invention is the organic electroluminescent diode not with inverted EL structure but with the more conventional EL structure configured.

in the Case of conventional EL structure, the organic electroluminescent diode is produced by a first electrode (anode), a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and a second electrode (cathode) in this order be deposited.

however is the organic electroluminescent diode in the inverted EL structure in reverse order to the conventional EL structure built up. That is, the organic electroluminescent diode thereby is made that a second electrode (cathode), an electron transport layer (ETL), an emission layer (EML), a hole transport layer (HTL), a hole injection layer (HIL) and a first electrode (anode) deposited in this order become.

Even though the inverted EL structure is proposed to make a problem more unstable Control with the AMOLED according to the relevant technology to solve, The interface tends to be between the organic emission layer and the anode to damage, and a characteristic of the device may be impaired.

As described above, the AMOLED is according to the relevant art with the conventional EL structure configured where the first electrode of the organic Electroluminescent diode is formed in a deeper part, so that it can be connected to the source electrode of the driver TFT. However, in the invention, the conventional EL structure is maintained, however, the second electrode of the organic electroluminescent diode is with connected to the drain electrode of the driver TFT.

Of the TFT array part of the AMOLED according to the invention has one Switching element, a driver element and a storage capacitor (not shown) for each pixel formed on the substrate. The switching element or the Driver element may be dependent configured by the operating characteristics through one or more TFTs be.

An AMOLED using an a-Si TFT is in the 5 shown. In this case, as it is in the 5 is shown, the n-type driver TFT.

According to the relevant art the driver TFT is an a-Si TFT of the n-type, and the first electrode of the organic electroluminescent diode is connected to the source electrode of the driver TFT. Accordingly, there is at the AMOLED according to the relevant technology a problem in that the device is driven unstably becomes. However, the invention can solve this problem by: the second electrode of the organic electroluminescent diode with the drain electrode of the driver TFT is connected while otherwise the conventional EL structure is maintained.

According to the 5 has the driver TFT T _D or 47 about one on a substrate 500 formed gate electrode 510 a gate insulating layer 520 and a source and a drain electrode 540 and 550 , The active layer 530 is between the source electrode 540 and the drain electrode 550 educated.

Also, the pixel area has a second electrode 600 the organic electroluminescent diode connected to the drain electrode 550 is connected, a multilayer or single-layer organic emission layer 590 that under the second electrode 600 is formed, and a first electrode 570 for injecting holes into the organic emission layer 590 ,

The second electrode 600 acts to inject electrons into the organic emission layer 590 ,

That is, in manufacturing the organic electroluminescent diode, the conventional EL structure is applied so that the first electrode 570 , the organic emission layer 590 and the second electrode 600 be prepared sequentially. This is the second electrode made at the top 600 with the drain electrode 550 connected to the driver TFT TD.

Furthermore, if the organic emission layer 590 is formed with a plurality of layers, which are prepared by forming a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML) and an electron transport layer (ETL) in this order on the first electrode 570 be deposited.

Here, the pixel areas are arranged in a matrix configuration, and they are passed through barrier ribs 582 separated from each other.

In other words, according to the invention, the first electrode becomes 570 (the anode of the organic electroluminescent diode) as a common electrode on the substrate 500 made on which the driver TFT TD is formed. Around the drain electrode 550 of the driver TFT TD is at the first electrode 570 and a passivation layer 560 on the drain electrode 550 are formed, a contact hole (not shown) is formed.

Furthermore, the barrier rib 582 on a predetermined part of the first electrode 570 made to divide the pixel areas. The organic emission layer 590 with the hole injection layer (HIL), the hole transport layer (HTL), the emission layer (EML), and the electron transport layer (ETL) within the barrier rib 582 divided pixel area. Then, the second electrode acting as the pixel electrode becomes 600 on the organic emission layer 590 produced. Accordingly, the second electrode becomes 600 and the drain electrode 550 connected to each other via the contact hole.

As shown, the second electrodes formed in the respective pixel areas are 600 through the barrier ribs 582 separated from each other, and the first electrode 570 is formed on the entire substrate except for a region where the contact hole is formed, thereby providing connection from one pixel to the other.

The following is with reference to the 6 a method for producing the AMOLED according to the invention described in detail.

The 6A to 6F Fig. 3 are sectional views illustrating a method of manufacturing the AMOLED according to the invention. In particular, the 6A to 6F Sectional views illustrating a manufacturing process for in the 5 represented area, ie the area with the driver TFT of the TFT array part.

According to the 6A is on a substrate 500 an a-Si TFT is made.

That is, the TFT in each on the substrate 500 formed pixel region is produced as a switching element or driver element. In the 6 it is shown as formed in each pixel area driver transistor T _D.

The a-Si TFT has a gate electrode 510 a gate insulating layer 520 , an active layer 530 and a source electrode 540 and a drain electrode 550 which are consecutive on the substrate 500 are separated. The active layer 530 is made of a-Si, and in this An example is the T-type N-type TFT.

The TFT is made by several mask processes. More recently, it is common for the active layer 530 and the source and drain electrodes 540 and 550 by a one-time masking process, so that the manufacturing process is shortened.

According to the 6B is on the resulting structure, where the TFT on the substrate 500 is formed, a passivation layer 560 produced. On this passivation layer 560 is a first electrode (anode) acting as a common electrode 570 produced.

The passivation layer 560 can be prepared as silicon nitride layer, silicon oxide layer or from BCB, photo acrylic, etc. The first electrode 570 In the exemplary embodiment, the electrode relates to the organic electroluminescent diode, and it may be made of a transparent material such as indium-tin oxide (ITO) or a colored metal such as aluminum (Al) and chromium (Cr).

If An a-Si TFT is used as a TFT, its size becomes large. Therefore is generally an up-emitting type instead of a used down-emitting type.

When the first electrode acting as a common electrode 570 is made of a transparent material such as ITO, it is preferable to use a metal layer (not shown) acting as a reflector in a lower part of the first electrode 570 manufacture.

If, however, the first electrode 570 is made of a colored metal such as aluminum (Al) or chromium (Cr), no reflector must be formed.

According to the 6C becomes the drain electrode 550 of the driver TFT T _D exposing contact hole 572 in a part of the passivation layer 560 and the first electrode 570 on the drain electrode 550 are formed, manufactured. The contact hole 572 is used to make a second electrode 600 with the drain electrode 550 connect to. Also, since the contact hole remains 572 only in a predetermined part above the drain electrode 550 is formed, the first electrode 570 still on the entire area of the pixel area. That is, the first electrode 570 is formed on the entire area of the pixel area except for the area where the contact hole 572 is formed so as to provide a connection from one pixel to another. According to the 6B become a buffer layer 580 and a barrier rib 582 on a predetermined part of the top of the first electrode 570 produced. The buffer layer 580 forms a region in which an organic emission layer is produced, and the barrier rib 582 divides the respective pixel areas.

That is, the buffer layer 580 exists at the periphery of an area where the organic emission layer 590 is formed within the pixel region, so that the organic emission layer 590 not in an area except the buffer layer 580 can be produced. The barrier rib 582 is on a predetermined part of the top of the buffer layer 580 and separates the pixel areas from each other.

According to the 6E becomes the organic emission layer 590 within the through the buffer layer 580 made area formed.

The organic emission layer 590 can be made with a multilayer or single-layer structure, the multilayer structure being common. In the case of the multi-layered structure, the organic emission layer has 590 via a hole injection layer (HIL) 592 , a hole transport layer (HTL) 594 , an emission layer (EML) 596 and an electron transport layer (ETL) 598 in this order on the first electrode 570 be deposited.

Because the organic emission layer 590 within the through the buffer layer 580 is formed, it is not formed in the area in which the contact hole 572 is trained.

According to the 6F becomes a second electrode acting as a pixel electrode 600 made so that they and the drain electrode 590 through the contact hole 572 connected to each other. As shown, the second electrodes are 600 in each pixel area through the barrier rib 582 separated from each other.

Since the up-emissive type can be used in the AMOLED according to the invention, the second electrode 600 can be made of a metal that can transmit light, or with a thickness below 100 Å (10 nm), so that light passes through the second electrode 600 can occur.

In the 7A to 7F another embodiment of the invention for making an AMOLED is illustrated.

According to the 7A is on a substrate 500 an a-Si TFT is made. That is, a TFT in each on the substrate 500 formed pixel region as a switching element or driver element becomes. As an example, a driver transistor T _{D is} illustrated. The a-Si TFT has a gate electrode 510 a gate insulating layer 520 , an active layer 530 and a source and a drain electrode 540 and 550 which are consecutive on the substrate 500 are separated.

The active layer 530 is made of a-Si, and in this example, the TFT is n-type. The TFT is made by several mask processes. More recently, it is common for the active layer 530 and the source and drain electrodes 540 and 550 by a one-time masking process, so that the manufacturing process is shortened.

According to the 7B is on the resulting structure, where the TFT on the substrate 500 is formed, a passivation layer 760 produced. This passivation layer 760 becomes a contact hole 762 structured. The passivation layer 760 can be prepared as silicon nitride layer, silicon oxide layer or from BCB, photo acrylic, etc.

After that, as it is in the 7C is illustrated, a first electrode (anode) 770 on the passivation layer 760 manufactured and structured so that it has a contact hole that the contact hole 762 through the passivation layer. The first electrode 770 in the exemplary embodiment, the anode is the organic electroluminescent diode, and it may be made of a transparent material such as indium-tin oxide (ITO) or a colored metal such as aluminum (Al) and chromium (Cr). Part of the top of the drain electrode 550 gets through the contact hole 762 exposed.

As above with respect to the embodiment of the 6 As discussed above, when an a-Si TFT is used as a TFT, its size becomes large. Therefore, the up-emitting rather than the down-emitting type is generally used. When the first electrode acting as a common electrode 770 is made on a transparent material such as ITO, it is preferable to use a reflector metal layer (not shown) on a lower part of the first electrode 770 manufacture. However, the reflector does not need to be manufactured when the first electrode 770 made of a colored metal such as aluminum (Al) or chromium (Cr).

According to the 7D become a buffer layer 780 and a barrier rib 782 on a predetermined part of the top of the first electrode 770 produced. The buffer layer 780 surrounds a region in which an organic emission layer is produced, and the barrier rib 782 splits the respective pixel areas.

According to the 7E becomes the organic emission layer 790 within the through the buffer layer 780 made area formed.

The organic emission layer 790 may be a multi-layered or single-layered structure, the multi-layered structure being common. In the case of the multi-layered structure, the organic emission layer has 890 via a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML) and an electron transport layer (ETL) arranged in this order on the first electrode 770 be deposited.

Because the organic emission layer 790 within the through the buffer layer 780 is formed in the area formed in which the contact hole 762 is trained.

According to the 7F becomes a second electrode acting as a pixel electrode 792 made so that they and the drain electrode 550 over the contact hole 762 connected to each other. As shown, the second electrodes are 792 in each pixel area through the barrier rib 782 separated.

In the 8A to 8F another embodiment of the invention for making an AMOLED is illustrated.

According to the 8A becomes an a-Si TFT on a substrate 500 produced. That is, a TFT in each on the substrate 500 formed pixel region is produced as a switching element or driver element. As an example, a driver transistor T _{D is} shown. The a-Si TFT has a gate electrode 510 a gate insulating layer 520 , an active layer 530 and a source and a drain electrode 540 and 550 which are consecutive on the substrate 500 be deposited.

The active layer 530 is made of a-Si, and in this example, the TFT is n-type. The TFT is made by several mask processes. More recently, it is common for the active layer 530 and the source and drain electrodes 540 and 550 by a one-time masking process, so that the manufacturing process is shortened.

According to the 8B becomes a passivation layer 860 fabricated on the resulting structure where the TFT is on the substrate 500 is trained. The passivation layer 860 can be prepared as a silicon nitride layer, as a silicon oxide layer or from BCB, photo acrylic, etc. After that, on the passivation layer 860 a first electrode (anode) 870 produced. After that, the passivation layer 860 and the first electrode 870 structured to a contact hole 862 form a part of the drain electrode 550 exposes. The first electrode 870 In the exemplary embodiment, the anode is the organic electroluminescent diode, and it may be made of a transparent material such as indium-tin oxide (ITO) or a colored metal such as aluminum (Al) and chromium (Cr). Part of the top of the drain electrode 550 is through the contact hole 862 exposed.

As stated above with regard to the embodiment of 6 is discussed, when TFT is used as an a-Si TFT, its size becomes large. Therefore, the up-emitting type is generally used instead of the down-emitting type. When the first electrode acting as a common electrode 870 is made of a transparent material such as ITO, it is preferable to use a metal layer (not shown) serving as a reflector on a lower part of the first electrode 870 manufacture. However, the reflector does not need to be manufactured when the first electrode 870 made of a colored metal such as aluminum (Al) or chromium (Cr).

According to the 8D become a buffer layer 880 and a barrier rib 882 on a predetermined part of the top of the first electrode 870 produced. The buffer layer 880 surrounds a region in which an organic emission layer is produced, and the barrier rib 882 splits the respective pixel areas.

According to the 8E becomes the organic emission layer 890 within the through the buffer layer 880 made area formed.

The organic emission layer 890 can be prepared as a multilayer or single-layer structure, the multilayer structure being common. In the case of the multi-layered structure, the organic emission layer has 890 via a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML) and an electron transport layer (ETL) arranged in this order on the first electrode 870 be deposited.

Because the organic emission layer 890 within the through the buffer layer 880 is formed in the area formed in which the contact hole 862 is trained.

According to the 8F becomes a second electrode acting as a pixel electrode 892 made so that they and the drain electrode 550 over the contact hole 862 connected to each other. As shown, the second electrodes are 862 in each pixel area through the barrier rib 882 separated from each other.

According to the invention is the drain electrode of the driver TFT with the second electrode the organic electroluminescent diode connected. Also keeps the invention the conventional one EL structure, as with the relevant Technique, in, so that the organic electroluminescent device can be easily and stably controlled.

Further be, in the AMOLED invention, the TFTs are produced as driving elements of the pixels as amorphous TFTs, and the second electrode (cathode) of the organic electroluminescent diode is connected to the drain electrode of the driver TFT, so that the Organic electroluminescent device are driven stable can.

Claims (31)

Method for producing an organic electroluminescent device, comprising: - producing a thin-film transistor (T _D ) on a substrate ( 500 ); - producing a passivation layer ( 560 ) on the substrate ( 500 ) with the thin film transistor (T _D ); - producing a first electrode layer ( 570 ) on the passivation layer ( 560 ); - establishing a contact hole ( 572 ) through the passivation layer ( 560 ) and the first electrode layer ( 570 ); Exposing a surface of a drain electrode ( 550 ) of the thin film transistor (T _D ) in a predetermined part of the first electrode ( 570 ) and the drain electrode; - producing a buffer layer ( 580 ) on a predetermined part of the top of the first electrode ( 570 ); - producing an organic emission layer ( 590 ) within a through the buffer layer ( 580 ) formed area; and - producing a second electrode ( 600 ) in such a way on the organic emission layer ( 590 ) that this second electrode ( 600 ) through the contact hole ( 572 ) through with the drain electrode ( 550 ) connected is. Method for producing an organic electroluminescent device, comprising: - producing a thin-film transistor (T _D ) on a substrate ( 500 ); - producing a passivation layer ( 760 ) on the substrate ( 500 ) with the thin film transistor (T _D ); - structuring the passivation layer ( 760 ) for forming a contact hole ( 762 ); - producing a first electrode layer ( 770 ) on the passivation layer ( 760 ); - structuring of the first electrode layer ( 770 ) for making a contact hole that the contact hole ( 762 ) through the passivation layer ( 760 ) and exposing the top of a drain electrode ( 550 ) of the thin film transistor (T _D ) in a predetermined part of the first electrode ( 770 ) and the passivation layer ( 760 ); - producing a buffer layer ( 780 ) on a predetermined part of the top of the first electrode ( 770 ); - producing an organic emission layer ( 790 ) within a through the buffer layer ( 780 ) formed area; and - producing a second electrode ( 792 ) on the organic emission layer ( 790 ) in such a way that this second electrode ( 792 ) through the contact hole ( 762 ) through with the drain electrode ( 550 ) connected is. Method for producing an organic electroluminescent device, comprising: - producing a thin-film transistor (T _D ) on a substrate ( 500 ); - producing a passivation layer ( 860 ) on the substrate ( 500 ) with the thin film transistor (T _D ); - producing a first electrode layer ( 870 ) on the passivation layer ( 860 ); - structuring of the first electrode layer ( 870 ) for forming a contact hole; - structuring the passivation layer ( 860 ) for forming a contact hole ( 862 ), which passes through the first electrode layer ( 870 ) and exposing the top of a drain electrode ( 550 ) of the thin film transistor (T _D ) in a predetermined part of the first electrode ( 870 ) and the passivation layer ( 860 ); - producing a buffer layer ( 880 ) on a vorbestimm th part of the top of the first electrode ( 870 ); - producing an organic emission layer ( 890 ) within a through the buffer layer ( 880 ) formed area; and - producing a second electrode ( 892 ) in such a way on the organic emission layer ( 890 ) that this second electrode ( 892 ) through the contact hole ( 862 ) through with the drain electrode ( 550 ) connected is. Method according to one of Claims 1, 2 or 3, in which the thin-film transistor (T _D ) is produced by using a gate electrode ( 510 ), a gate insulating layer ( 520 ), an active layer ( 530 ), an ohmic contact layer, a source electrode ( 540 ) and a drain electrode ( 550 ) are sequentially deposited. Method according to claim 4, wherein the active layer ( 530 ) is made of a-Si and the n-type thin film transistor. Method according to one of claims 1 to 5, wherein the first Electrode of ITO (indium tin oxide), which is a transparent, conductive Material is produced. Method according to one of claims 1 to 5, wherein the first Electrode is made of an opaque metal, the is selected from the group consisting of Al and Cr. The method of claim 6, further comprising manufacturing an opaque metal layer as a reflector under the first Electrode. Method according to one of claims 1 to 8, wherein the first Electrode made in a field except one area becomes, in which the contact hole is formed. Method according to one of claims 1 to 9, wherein the buffer layer at the periphery of a pixel area, where the organic emission layer is produced is formed. Method according to Claim 10, in which a barrier rib ( 582 . 782 . 882 ) is made to separate the pixel area from an adjacent pixel area. The method of claim 11, wherein the barrier rib is produced on the buffer layer. Method according to one of claims 1 to 12, wherein the organic Emission layer is produced by using a HIL, an HTL, an EML and an ETL are sequentially deposited on the first electrode become. The method of claim 10, wherein the second Electrodes in each pixel area through the barrier rib from each other be separated. Method according to one of claims 1 to 14, wherein the second Electrode is made of a transparent metal. Method according to one of claims 1 to 15, wherein the second Electrode a thickness below about 100 Å, so that light can shine through them. Method according to one of claims 1 to 16, wherein the first Electrode is an anode and the second electrode is a cathode. Organic electroluminescent device with: A plurality of TFTs on a substrate ( 500 ); A passivation layer ( 560 . 760 . 860 ) and a first electrode ( 570 . 770 . 870 ) on the substrate with the TFTs; - a contact hole ( 572 . 762 . 862 ) through a predetermined portion of the first electrode and the passivation layer, around the top of a drain electrode (Fig. 550 ) of the thin film transistor; A buffer layer ( 580 . 780 . 880 ) on a predetermined part of the top and an edge of the first electrode; - an organic emission layer ( 590 . 790 . 890 ) within a region formed by the buffer layer; and a second electrode ( 600 . 792 . 892 ) on the organic emission layer, and electrically through the contact hole with the drain electrode ( 550 ) connected is. An organic electroluminescent device according to claim 18, wherein the thin film transistor is connected via a gate electrode ( 510 ), a gate insulating layer ( 520 ), an active layer ( 530 ), an ohmic contact layer, a source electrode ( 540 ) and the drain electrode ( 550 ). An organic electroluminescent device according to claim 19, wherein the active layer ( 530 ) is made of a-Si and the thin film transistor is n-type. Organic electroluminescent device according to claim 18, in which the first electrode is a transparent, conductive material contains. Organic electroluminescent device according to claim 18, in which the first electrode contains an opaque metal, the is selected from the group consisting of Al and Cr. Organic electroluminescent device according to claim 21, further with an opaque acting as a reflector Metal layer under the first electrode. Organic electroluminescent device according to claim 18, in which the first electrode in an area except one Is present area in which the contact hole is formed. Organic electroluminescent device according to claim 18, where the buffer layer is at the periphery of a pixel area, where the organic emission layer is formed, is present. An organic electroluminescent device according to claim 25, further comprising a barrier rib ( 582 . 782 . 882 ) that separates adjacent pixel areas. Organic electroluminescent device according to claim 18, in which the organic emission layer via a HIL, a HTL, a EML and an ETL on the first electrode features. Organic electroluminescent device according to claim 26, in which the second electrodes in each pixel area through the Barrier rib are separated from each other. Organic electroluminescent device according to claim 18, in which the second electrode contains a transparent metal. Organic electroluminescent device according to claim 18, in which the second electrode has a thickness below 100 Å, so that light can shine through them. Organic electroluminescent device according to claim 18, in which the first electrode is an anode and the second electrode a cathode is.